Defensive publication

ABSTRACT

THE PRESENT INVENTION RELATES TO IMPROVEMENTS IN A METHOD OF THE CASING MAGNESIUM BASE ALLOYS TO REDUCE MELT LOSS. SUCH IMPROVEMENTS COMPRISE EMPLOYING CERTAIN MAGNESIUM BASE ALLOYS AND/OR LUBRICANTS, THE LATTER BEING CONTROLLED IN QUANTITY AND/OR PLACE OF APPLICATION SO AS TO INHIBIT THE FORMATION OF A MATERIAL, PRESUMABLY MANGANESE-CARBON PARTICLES, WHICH STABILIZES THE FLUX-METAL EMULSION IN THE MAGNESIUM ALLOY MELT BEING DIE CAST. IT HAS BEEN DISCOVERED THAT SUCH STABILIZER MATERIAL SURROUNDS OR ENTRAPS METAL GLOBULES IN THE SLUDGE LAYER OF THE MAGNESIUM ALLOY MELT CAUSING A HIGH METAL LOSS. SUCH STABILIZERS CAN BE AVOIDED BY THE PRESENT METHOD BY, FOR EXAMPLE, USING A MAGNESIUM BASE ALLOY WITH A LOW MANGANESE CONTENT WHEN AN OIL BASE LUBRICANT IS EMPLOYED; APPLYING LUBRICANT TO THE DIE SURFACE OR DIE PLUNGER RATHER THAN TO THE SHOT WELL OF THE DIE CASTING MACHINE; USING A NON-CARBONACEOUS LUBRLCANT; OR REDUCING THE AMOUNT OF LUBRICANT NORMALLY USED IN THE DIE CASTING OPERATION.

DEEENSWE PUELTCATMN UNITED STATES PATENT OFFICE Published at the requestof the applicant or owner in accordance with the Notice of Dec. 16,1969, 869 O.G. 687. The abstracts of Defensive Publication applicationsare identified by distinctly numbered series and are arrangedchronologically. The heading of each abstract indicates the number ofpages of specification, including claims and sheets of drawingscontained in the application as originally filed. The files of theseapplications are available to the public for inspection and reproductionmay be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to themerits of alleged invention. The Patent OtIice makes no assertion as tothe novelty of the disclosed subject matter.

PUBLISHED NOVEMBER- 23, 1971 T892,017 METHOD (BF REDUCING MELT LOSS INDIE CASTENG MAGNESHUM BASE ALLOYS Stephen C. Erickson and John N.Reding, Midland, Mich,

assignors to The Dow Chemical Company, Midland,

Mich.

Filed Nov. 27, 197i), Ser. No. 116,694 lint. Cl. 132% 27/10 US. Cl.16472 N0 Drawing. 7 Pages Specification The present invention relates toimprovements in a method of die casting magnesium base alloys to reducemelt loss. Such improvements comprise employing certain magnesium basealloys and/or lubricants, the latter being controlled in quantity and/orplace of application so as to inhibit the formation of a material,presumably manganese-carbon particles, which stabilizes the flux-metalemulsion in the magnesium alloy melt being die cast. It has beendiscovered that such stabilizer material surrounds or entraps metalglobules in the sludge layer of the magnesium alloy melt causing a highmelt loss. Such stabilizers can be avoided by the present method by, forexample, using a magnesium base alloy With a low manganese content whenan oil base lubricant is employed; applying lubricant to the die surfaceor die plunger rather than to the shot Well of the die casting machine;using a non-carbonaceous lubricant; or reducing the amount of lubricantnormally used in the die casting operation.

